If you've been receiving the message "The domain mydomain.com (username) has reached 80% of its bandwidth limit. Please contact the system admin as soon as possible." , that mean you'll need to upgrade your hosting plan, This is a system warning that indicate you are about to exceed your bandwidth limits and you should contact us to upgrade your account before it's automatically suspended by the system.
All you have to do is open a ticket and let us know which plan you like to upgrade to, we will upgrade your account as indicated in the ticket and send you an invoice with the difference